1. Field of the Invention
The invention relates to a filter, and more particularly, to a filter whose order is enhanced by applying a high-pass network for an input signal.
2. Description of the Related Art
Generally, attenuation of a filter can be enhanced by increasing the order of the filter. It has been known that the value of the order of the filter is equal to the number of operational amplifiers in the filter. Moreover, the number of feedback capacitors of the filter is also increased with the increment of the order of the filter. Thus, when a filter is required to have a high order, the number of operational amplifiers in the filter and the number of feedback capacitors become larger, resulting in a large area occupied by the filter.